Switching from Tier2 to Tier1 Dependant

[jej_sk]

Hello,

Can anyone please help me with this information:

1. I am currently on Tier2 visa(Intra company transfer) and I am planning to switch to a Tier1 dependant. Would it be possible to do this while I am in the UK or do I have to go back to my home country and then apply for a Tier1 dependant.

2. If I cannot change my visa here and have to go back to my home country, would it be possible for me to stay back for a couple of months after I have quit my company. I have a medical condition because of which I cannot travel right away. If I get a letter from the GP, would it be ok for me to overstay and not have any problems when I apply for my Tier1 dependant visa.

Thanks in advance for your help.